1. Field of the Invention
The present invention relates to a jukebox apparatus, and in particular, the present invention relates to a jukebox apparatus having a retry control system for transferring a data storing device between a carriage and a magazine and between the carriage and a drive unit.
2. Description of the Related Art
Electronic filing systems have been developed which use large capacity data storing devices such as optical or magnetic diskas. Electronic filing systems include jukebox apparatuses or library apparatuses accommodating a plurality of optical or magnetic disks therein so that one of the optical or magnetic disks can be selected and used in a drive unit.
A known jukebox apparatus includes a magazine having a plurality of slots for accommodating data storing devices (disks) therein, a drive unit having a slot for receiving a selected disk and a read/write head, and a conveying device for conveying a disk between the magazine and the drive unit. Such a jukebox apparatus is proposed in Japanese Patent Application No. 5-244935, filed Sep. 30, 1993, by the assignee of the present case. This jukebox apparatus includes a magazine, a drive unit, a conveying device, and a temporary storage unit.
The conveying device includes a carriage for conveying a disk between the magazine and the drive unit along a predetermined conveying path. The carriage has a transferring device for transferring a disk between the carriage and the magazine and between the carriage and the drive unit. In the above described Japanese Patent Application, the transferring device comprises a pair of gripping arms, pairs of pinch rollers, and a pushing arm. The temporary storage unit is arranged oppositely to the drive unit so that the temporary storage unit is moved between a transfer position in front of the drive unit and an escape position in which the temporary storage unit is retracted from the conveying path of the carriage so that the carriage can convey a disk to the drive unit.
When one disk is used in the drive unit and a new disk is requested, i.e., when the disk change is requested, the temporary storage unit is moved to the transfer position and the old disk is transferred from the drive unit to the temporary storage unit. The temporary storage unit is then moved to the escape position, and the carriage conveys a new disk from the magazine to the drive unit. Therefore, it is possible to quickly change the disks. After the new disk is transferred from the carriage to the drive unit, the old disk is transferred from the temporary storage unit to the carriage and the carriage conveys the old disk to the magazine. The old disk is then transferred from the carriage the magazine.
In this jukebox apparatus, the carriage is moved to a reference position in front of the magazine or the drive unit when the carriage conveys a disk to the magazine or the drive unit for transferring the disk. The reference position is predetermined, and the carriage is directly moved to the reference position. However, mechanical components are not always accurately fabricated and assembled, so the predetermined reference position is not always an optimum position to transfer a disk. If the reference position is not appropriate, there may be a problem that the disk cannot be transferred between the carriage and the magazine or the drive unit.
Further, when a disk is transferred from the carriage to the drive unit, the disk is first advanced by the pinch rollers and then pushed by the pushing arm. When the disk is fully locked into the slot of the drive unit, the disk is locked in the drive unit. The pushing arm is operated for a predetermined pushing time. However, if the pushing time is too long, the disk is excessively pushed and the drive unit may be damaged or the drive unit may make noise. If the pushing time is too short, the disk is insufficiently pushed and the drive unit may fail to lock the disk.
Therefore, it is necessary to select the pushing time so that the disk is appropriately set in the drive unit and an undesirable load is not applied to the drive unit. However, in this case too, there is a problem of an inaccuracy of mechanical components and assemblies, so it is difficult to select an optimum pushing time. In addition, a change in temperature during use may make it difficult to determine an optimum pushing time.
Further, the temporary storage unit is usually maintained at the escape position. However, if vibration occurs in the jukebox apparatus, for example, the temporary storage unit may be undesirable moved and displaced away from the escape position toward the conveying path of the carriage. A problem may occur if the temporary storage unit is displaced away from the escape position and projects into the conveying path when the carriage is moving toward the drive unit. In addition, if the temporary storage unit is not exactly placed at the transferring position when the disk is transferred from the drive unit to the temporary unit, a disk may not be transferred.